Specific anti-toxoplasmic IgG antibody immunoblot profiles in patients with AIDS-associated Toxoplasma encephalitis

Abstract

Among 186 suspected cases of Toxoplasma encephalitis (TE) in HIV-infected patients, 113 were classified as TE and 73 as non-TE. Serum Toxoplasma gondii (T.g.) antibodies were detected by ELISA in 97% of TE vs 71% of non-TE cases (p < 0.001). In the 164 patients positive for T. g. antibodies, the IgG 27 and 32 bands were more frequently present in TE than in non-TE (p = 0.003, p = 0.002, respectively). Among patients with positive T.g. serology, multivariate analysis showed that the presence of an IgG 32 (OR 3.1) or IgG 27 band (OR 2.7) on Western blot was highly indicative of TE independently of each other. Positive T.g. serology, but not anti-T.g. IgG antibody titres, was predictive. Thus, the positivity of IgG 27 and 32 bands on Western blot analysis provides useful data for improving the diagnosis of presumptive TE in HIV-infected patients with suspected TE and positive Toxoplasma serology.